Food waste is a sustainable and carbon-neutral source of organic compounds, and thus developing an efficient approach for conversion of food waste into chemicals and fuels is one of the most promising ways to contribute to sustainable development. Herein, a facile and rapid method for hydrothermal conversion of food waste with complex components and high water content into formate, which is regarded as an excellent hydrogen storage carrier and as fuel cell material recently, is proposed for the first time. The results showed not only that purified starch and cellulose, which are the major compositions of food waste, but also the real components of food waste, as well as simulated food waste, could be converted efficiently to formate with high yields of 40-78%. Also, it was found that there was no significant disturbance between different components in formate production. This study may provide a promising method for the energy valorization of high water content and complex organic municipal waste.